Longitudinal wave function control in single quantum dots with an applied magnetic field

Cao, Shuo; Tang, Jing; Gao, Yunan; Sun, Yue; Qiu, Kangsheng; Zhao, Yanhui; He, Maowei; Shi, Jinan; Gu, Lin; Williams, D. A.; Sheng, Weidong; Jin, Kuijuan; Xu, Xiulai

doi:10.1038/srep08041

Cited by 17 publications

(20 citation statements)

References 45 publications

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“…This technique enabled us to find a suitable region where the dot density is low enough to address single QDs. Pyramidal QDs with a diameter of 20 nm and height of 6 nm having the Zincblende structure were observed by high-resolution cross-section transmission electron microscopy, as reported previously [42].…”

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confidence: 53%

“…However, for very thin quantum wells (less than 5 nm thick) with finite potential confinement, an increase of γ has been observed with the decrease of the well width because of the expansion of the wavefunction into the barrier regions [38]. The monolayerthick wetting layer can be considered as a thin quantum well, as characterized by transmission electron microscopy [34,35,42]. In a system with a single QD coupled with a wetting layer, the optically generated electrons using high excitation power occupy either the wetting layer or excited states in the QDs.…”

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confidence: 99%

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Observation of coupling between zero- and two-dimensional semiconductor systems based on anomalous diamagnetic effects

et al. 2015

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We report the direct observation of coupling between a single self-assembled InAs quantum dot and a wetting layer, based on strong diamagnetic shifts of many-body exciton states using magneto-photoluminescence spectroscopy. An extremely large positive diamagnetic coefficient is observed when an electron in the wetting layer combines with a hole in the quantum dot; the coefficient is nearly one order of magnitude larger than that of the exciton states confined in the quantum dots. Recombination of electrons with holes in a quantum dot of the coupled system leads to an unusual negative diamagnetic effect, which is five times stronger than that in a pure quantum dot system. This effect can be attributed to the expansion of the wavefunction of remaining electrons in the wetting layer or the spread of electrons in the excited states of the quantum dot to the wetting layer after recombination. In this case, the wavefunction extent of the final states in the quantum dot plane is much larger than that of the initial states because of the absence of holes in the quantum dot to attract electrons. The properties of emitted photons that depend on the large electron wavefunction extents in the wetting layer indicate that the coupling occurs between systems of different dimensionality,which is also verified from the results obtained by applying a magnetic field in different configurations. This study paves a new way to observe hybrid states with zero-and two-Nano Res. dimensional structures, which could be useful for investigating the Kondo physics and implementing spin-based solid-state quantum information processing.Semiconductor quantum dots (QDs), also known as "artificial atoms", have attracted considerable interest because of their application to quantum optoelectronic devices such as singlephoton sources [1-6], quantum bits [7,8], quantum logic gates [9], and photon-spin interfaces [10][11][12]. Owing to the quasi-zero-dimensional nature of QDs, many-body effect induced exciton states have been achieved in single QDs by controlling charge states with external electric and magnetic fields [13][14][15]. Following the discovery of graphene [16], two-dimensional materials, such as MoS2 [17, 18] and black phosphorous [19], have been investigated extensively. Recently, the coupling between QDs and two-dimensional extended states has been investigated to demonstrate the Kondo physics [15,[20][21][22][23][24] and Fano effect [25,26]. Hybridization between a single QD and a twodimensional continuum state has been studied experimentally and theoretically in various systems [21,[27][28][29][30][31][32]. For self-assembled QDs grown by molecular beam epitaxy (known as Stranski-Krastanov growth), a wetting layer with a thickness of a few monolayers is always formed underneath the QDs [33][34][35], which naturally provides a platform for the formation of coupled systems for many-body exciton states [15,27]. Karrai et al. [27] have shown the coherent hybridization of localized QD states and extended continuum states in the wetting la...

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confidence: 53%

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confidence: 99%

Observation of coupling between zero- and two-dimensional semiconductor systems based on anomalous diamagnetic effects

et al. 2015

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“…The QDs in this sample have a truncated pyramid structure, as shown in the high-resolution cross section image of a single QD by transmission electron microscopy in Fig. 3(a) 15 . For the heavy hole in pure InAs QDs, the confining potential increases linearly from the bottom to the apex based on the eight-band k·p calculation 30,31 .…”

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confidence: 88%

Tuning the carrier tunneling in a single quantum dot with a magnetic field in Faraday geometry

Peng

Xie

et al. 2019

Applied Physics Letters

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We report on an increase in the carrier tunneling time in a single quantum dot (QD) with a magnetic field in Faraday geometry using photocurrent spectroscopy.A nearly 60% increase in hole tunneling time is observed with an applied magnetic field equal to 9 T. For a truncated pyramid QD, hole tunnels out faster at the lateral edge of the QD due to the reduced barrier height. The magnetic field in Faraday

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“…It allows to predict accurate values of the charging energies of PQDs. Our predictions can be tested experimentally with well established methods like scanning tunneling spectroscopy [35][36][37].…”

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confidence: 99%

Conditions for the occurrence of Coulomb blockade in phosphorene quantum dots at room temperature

et al. 2018

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We study the addition energy spectra of phosphorene quantum dots focusing on the role of dot size, edges passivation, number of layers and dielectric constant of the substrate where the dots are deposited. We show that for sufficiently low dielectric constants (ε sub < 4), Coulomb blockade can be observed in dot sizes larger than 10 nm, for both passivated and unpassivated edges. For higher dielectric constants (up to ε sub = 30), Coulomb blockade demands smaller dot sizes, but this depends whether the edges are passivated or not. This dramatic role played by the substrate is expected to impact on the development of application based on phosphorene quantum dots. arXiv:1806.05731v1 [cond-mat.mes-hall]

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Longitudinal wave function control in single quantum dots with an applied magnetic field

Cited by 17 publications

References 45 publications

Observation of coupling between zero- and two-dimensional semiconductor systems based on anomalous diamagnetic effects

Observation of coupling between zero- and two-dimensional semiconductor systems based on anomalous diamagnetic effects

Tuning the carrier tunneling in a single quantum dot with a magnetic field in Faraday geometry

Conditions for the occurrence of Coulomb blockade in phosphorene quantum dots at room temperature

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